thirdgen

iTrader: (26)

Most I've ever seen on a GT2560, running exactly 11psi, was actually an FM II Kit. It hit 244whp with a hydra and 550's. 300? I think not. I think they're running Fertilizer injection, cause I smell the bullshit.

paul

iTrader: (21)

My car at 8.99psi with a gt2560, 99 motor made 246rwhp. MS and 550s. add 5psi(14psi) and it made only 300 but that's because i have no idea what the **** i'm doing with timing. I say I get my car to DIYAutotune to have them tune spark and fuel and shove that dyno up FM's ***. Does FM use dynapacks?

y8s

iTrader: (8)

rototest. same principle but uses hydraulic fluid instead of eddy current.

Ben

iTrader: (33)

what did it do uncorrected? would be nice to be able to compare uncorrected power at absolute pressure vs uncorrected power at absoulte pressure.

Braineack

iTrader: (62)

uncorrected it made 300rwhp

corrected using SAE (97%), smoothing of 5: 290.98rwhp

65°F, 42% humidity, 29.96 ~hg.

paul

iTrader: (21)

uncorrected:
9psi run was 247.62
14psi run was 301.46 hp

SAE correction applied:
9psi: 246.89
14psi: 300.28

files are here
14psi http://www.miatamx5.com/dynoruns/4-5.....REIN_003.drf
9psi http://www.miatamx5.com/dynoruns/4-5.....REIN_004.drf

edit. different from what brain posted because i use smoothing of ZERO

conditions:

29.96 in-Hg 14psi run
29.93 in-Hg 9 psi run

Braineack

iTrader: (62)

paul is yours above correct? I'm dropping 3% (10rwhp) from your charts.

Ben

iTrader: (33)

Damn son.

Still, based on your fuel system and 72% IJDC, I think that dyno was a little bit optomistic. 280 or so seems likely, 300 should have maxed out the 550s. You can't beat physics.

y8s

iTrader: (8)

paul, what was your fuel pressure? running > 60 psi fuel pressure on 550s means more than 300 rwhp.

Savington

iTrader: (31)

You can question all you want, actually. As long as both sides stay technical and nobody introduces personal bullshit, the thread could go on forever, and if a mod closed it they'd get called out on it.

Braineack

iTrader: (62)

remember, 13 other people all ran on that dyno that same morning. it was dynojet, not much you can do for fudging the numbers. He was stilling more power than the rest of us, even airbrush at the same boost level with his T3 (saw 260rwhp at 14psi).

Assuming 50psi at atmospheric, he should have something like 64psi in the rail. When I do the math for 325BHP at .72 DC and .55 BSFC, I get 538cc as the ideal injector.

Ben

iTrader: (33)

lulz, what math did you use? mine comes out different.

the other option is that his 550 injectors flow greater than 550 cc/min @ 3 bar. if they're rx7 tII injectors, those have been shown to flow 575-600 cc/min, and the numbers would make sense.

I ain't knockin paul. he's the one who started pulling the 'how come your IJDC is much higher than mine' train, so I'm looking for the answer.

paul

iTrader: (21)

i have an electronic fuel pressure gauge that shows the pressure right around 60. typically when the car is at that load i can't look at the gauge very long

Braineack

iTrader: (62)

60 / 43.5 = 1.379

Sqaure Root of 1.379 = 1.174308307047174

1.174 x 550cc = 645.7cc

645.7cc / 10.5 = 61.49 lb/min


(61.49 lb/min * .72) / .55 = 80HP

80.5HP * 4 cylinders = 322BHP

Ben

iTrader: (33)

got ya, I was figuring 50 psi fuel pressure.

remember the charge is pressurized, so you really should subtract boost from rail pressure to get differential fuel pressure.

Braineack

iTrader: (62)

well it's 1:1, so really it's all relative. the same fuel/air is being injected per each level of atmosphere...but the rail pressure is still increasing, so the fuel capacity is still be extended, correct?


maybe we need to see what Airbrush1 logged as his DC% on his 260rwhp run that afternoon.

paul

iTrader: (21)

just looked all over for the sheet from witch hunter for the 550's but can't find it. i think they tested at 550. supersaiyan might remember, i bought them off him

airbrush1

I didn't log anything that day, just did the pulls.

On my tuner's dynapack the car did 292 wheel, and I'm running low impedance
rx7 460's... I'm sure they wouldn't have maxed out my fuel completely

Mach929

iTrader: (3)

i've always run my calculations with the 1:1 in mind, 50psi at atmosphere plus whatever boost you're running, so at 15psi boost 65psi of fuel is considerably more fuel than at 50psi.

alternatively, why do we even need fuel pressure regulators?

paul

iTrader: (21)

i think it goes something like this:

our pumps would make 80+psi all the time which would
1. make it harder to idle the damn thing
2. burn the pump out faster
3. and that bitch would be loud